spiking across the country tonight in the wake ofthesandyhooktragedy. many bay area dealers telling us they can barely keep assault rifles on the shelves. people are buying them up. one of their best sellers, the ar-15 semiautomatic rifle, the same gun the sandy hook killer used. >> we've got a ton of new buyers, people that have never bought them before coming in to get one, because it may be their last chance to get one. >> federal background checks hit an all-time high last month, following president obama's reelection. >>> then there's the effort to get guns off the streets. it's going well in oakland so far. all week long, gun owners have been trading in their fire power for cash. the buyback has netted hundreds of weapons. >>> washington also got to work today on gun control. vice president joe biden convened the task force that will review the nation's gun laws and recommend changes. the president wants concrete proposals in hand by next month. the team will also look at mental health issues, school readiness, even violent video games. sharon chin shows us one bay area group is